Neck Exercises in Patients With Temporomandibular Disorders

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Musculoskeletal (MSK) pain is a common reason to seek medical treatment. Temporomandibular disorders (TMDs) are MSK disorders that affect the masticatory muscles, the temporomandibular joint, and related structures in the neck and head. Current research showed that people with chronic TMDs have structural and functional brain changes that may contribute to chronic pain development and maintenance. Therapeutic exercise is a central component in treating chronic MSK conditions. New therapies, including exercise, appear to have potential in targeting cortical changes to improve clinical outcomes. However, mechanisms of action are not well understood, and evidence is limited to a few weak studies and specific populations. Evidence from our research group highlights neck exercise as potentially useful in treating TMDs. However, we do not yet know how the brains of women with TMD respond to specific exercise and whether these changes relate to decreased pain, improved function, and quality of life. Evidence linking brain plasticity, pain modulation, and exercise therapy is currently limited, and non-existent for people with TMDs. Objectives: In women with chronic TMD pain, we will:1) determine the impact of motor control training using visual feedback (MCTF) on clinical outcomes such as pain intensity and jaw disability, 2) assess the impact of MCTF on brain structure, using diffusion tensor imaging, 3) assess the impact of MCTF on brain networks, using resting state functional magnetic resonance imaging, and 4) determine the effectiveness of MCTF to restore normal muscular structure, performance and fatigability of neck cervical muscles, using electromyographic analysis. Methods: Women with chronic TMD pain will be randomized to either an intervention arm or a placebo control group. Women in the intervention arm will receive 8 weeks of progressive exercise MCTF of the cervical muscles, twice per week. Women in the placebo arm will receive innocuous transcutaneous electrical nerve stimulation (turn off). Our primary outcomes will be changes in 1) pain, measured with the Visual Analogue Scale, 2) brain structure and networks, measured by fractional anisotropy (brain structure) and the blood-oxygen-level dependent signal (brain networks). Outcomes will be measured at baseline, after 8 weeks of treatment, and 4 months after treatment ends. Results will directly inform and guide clinicians in prescribing more effective interventions for women with TMD

A randomization sequence will be computer-generated by a research assistant (RA) not involved in the study. To ensure concealment, the RA will distribute the results of the sequence to the therapist in consecutively numbered, opaque, and sealed envelopes. Participants will be unaware of the study hypothesis. Assessors (who will measure clinician-assessed tests and analyze imaging outcomes) and the statistician will be blinded to the hypothesis and group allocation, following established guidelines. Participants randomized to the treatment group will receive MCTF as described in the Intervention section. Participants randomized to the placebo group will receive placebo transcutaneous electrical nerve stimulation (TENS) as described in the Intervention section

Masking:

Triple (Participant, Investigator, Outcomes Assessor)

Masking Description:

Patients (reporting one of the main outcome for this study - pain) will be unaware of the hypothesis of this study and performance biases will be avoided by telling them that both treatment options have similar effectiveness. Assessors (measuring clinician assessed tests) and Statistician will be blinded to hypothesis and group allocation following established guidelines.

Primary Purpose:

Treatment

Official Title:

Effectiveness of Neck Motor Control Exercises in Patients With Temporomandibular Disorders: A Pilot Randomized Controlled Trial

Neck flexors Training: Each patient will initially perform cranio-cervical flexion to sequentially reach 5 pressure targets in 2 mmHg increments from a baseline of 20 mmHg to the final level of 30 mmHg. For each target level, the contraction duration will be increased to 10 s, and the participant trained to perform 10 repetitions with brief rest periods between each contraction. Once one set of 10 repetitions of 10 s is achieved at one target level, the exercise will be progressed to train at the next target level up to the final target. Neck extensors training: Patients will perform cranio-cervical extension and upper cervical rotation in a prone on elbows position while maintaining the cervical spine in a neutral position, progressing to a 4-pt kneeling position.

Other: Exercises

The treatment will consist of an 8-week progressive exercise program of neck flexors and extensors exercises supervised by a physical therapist for 30-45 min twice a week per 8 weeks as described in Arm/group descriptions.

Placebo Comparator: Placebo

The placebo group will receive placebo TENS (switched-off TENS apparatus with no perceptible stimulation). Four electrodes, 50 x 35 mm, will be placed on the neck muscles. The participant will be informed that this therapy is called a "subthreshold current" and they might not be able to feel any sensation underneath the electrodes during the treatment. The placebo treatment will be for 30 min twice a week for 8 weeks, as for the intervention group.

Other: Placebo

The placebo treatment will be for 30-45 min twice a week for 8 weeks, as for the intervention group. ( see details in arm description)

The VAS is a linear scale 10 cm in length, labeled with the two extremes boundaries of pain sensation: "no pain", at one end and "worst pain imaginable" at the other end. The validity and reliability of these methods for determining pain intensity, has been reported and confirmed in the literature

To analyze the DTI images, we will use a method similar to Moayedi et al. To analyze the rsfMRI images, we will use the pipeline outlined in Greicius et al.in addition to applying functional connectivity (graphical modelling) as previously used in our lab. Images will be imported into the software library (FSL v. 4.1.8) of the Oxford Centre for Functional MRI of the Brain (FMRIB). Preprocessing will include current and motion artifact correction using the FMRIB Diffusion Toolbox v. 2.0. The DTI images will be processed through 2 different pipelines for 1) voxel-wise analysis and 2) tractography. The preprocessed images will be fit with a diffusion tensor model using DTIFIT in the FDT. We then will calculate voxel-wise values of FA. The rsfMRI images will be analyzed using an ICA approach to isolate the DMN and the sensorimotor network and a functional connectivity approach using graphical modelling to assess the neural networks associated with TMD treatment.

To analyze the DTI images, we will use a method similar to Moayedi et al. To analyze the rsfMRI images, we will use the pipeline outlined in Greicius et al.in addition to applying functional connectivity (graphical modelling) as previously used in our lab. Images will be imported into the software library (FSL v. 4.1.8) of the Oxford Centre for Functional MRI of the Brain (FMRIB). Preprocessing will include current and motion artifact correction using the FMRIB Diffusion Toolbox v. 2.0. The DTI images will be processed through 2 different pipelines for 1) voxel-wise analysis and 2) tractography. The preprocessed images will be fit with a diffusion tensor model using DTIFIT in the FDT. We then will calculate voxel-wise values of FA. The rsfMRI images will be analyzed using an ICA approach to isolate the DMN and the sensorimotor network and a functional connectivity approach using graphical modelling to assess the neural networks associated with TMD treatment.

Will be measured using a self-reported questionnaire called "Limitations of Daily Functions in TMD Questionnaire" (LDF-TMDQ/JFS, available upon request).The internal consistency of this questionnaire is high and there is good convergent validity with the dental version of the McGill Pain Questionnaire.The total score of the questionnaire summing the patient's answers will be used for statistical purposes.

The subjects will be asked to perform a maximal isometric cervical extension contraction (MVC) (for 5 seconds). Once the tester has ensured that the subject has learned the procedure, each subject will be asked to perform the maximal voluntary isometric contraction (MVC). Each subject will perform 2 repetitions of this movement allowing 5 minutes between each trial to avoid fatigue. The average force value of the 2 contractions will be used as the reference MVC. This will allow submaximal target contractions (25% MVC) to be set on the visual feedback display related to this value. After performing the MVC, and when the tester has ensured that the subject had learned the procedure for doing submaximal contractions with the help of the visual biofeedback, each subject will be asked to perform 2 submaximal cervical flexion contractions at 25% MVC, keeping the chin retracted, and maintain these contractions if possible using a visual display for feedback of the force output.

Subjects will be asked to perform a maximal isometric cervical flexion contraction (MVC) (for 5 seconds). Each subject will perform 2 repetitions of this movement allowing 5 minutes between each trial to avoid fatigue. The average force value of the 2 contractions will be used as the reference MVC. This will allow submaximal target contractions (25% MVC) to be set on the visual feedback display related to this value. After performing the MVC, and when the tester has ensured that the subject had learned the procedure for doing submaximal contractions with the help of the visual biofeedback, each subject will be asked to perform 2 submaximal cervical flexion contractions at 25% MVC, keeping the chin retracted, and maintain these contractions as long as possible using a visual display for feedback of the force output.

CCFT is performed using a pressure biofeedback device located in the neck region, and a visual aid positioned in front of the subject, with the subject lying supine, keeping the legs flexed. Each subject will be attempted to reach 5 different levels. The device will have a graduation with marks corresponding to increments of 2mmhg, ranging from 20mmhg to 30mmhg. The level of effort required in the test will be progressive, and observed according to what the subject can perform. To move to the next level, the subject must be able to complete ten 10-second repetitions on each possible level. When the subject starts to use the superficial musculature or to do some compensation of the movement, it will be time to finish the test. The cumulative performance Index (CPI) will be calculated. A perfect CPI of 300 will be obtained if the participant could progress through all levels without showing signs of compensations and/or fatigue.

All Subjects will be asked to rate the change they have experienced in jaw pain and jaw function before and after the treatment using a global rating scale (GRS). This scale can be used by subjects to rate the magnitude of change they have experienced, in this case, after the exercise therapy at two and at six months. Subjects will identify the degree of change by responding on a 15-point Likert scale, with -7 = a very great deal worse, 0 = about the same, and +7 = a very great deal better.

Is a 10-item questionnaire that measures how much neck pain affects activities of daily living such as personal care, lifting, reading, headaches, concentration, work, driving, and sleeping. The NDI is a validated, reliable and responsive relatively short questionnaire that can be easily administered. For the purpose of this study, the total score of the questionnaire summing the patient's answers was used for statistical purpose.

Pressure pain sensitivity (PPS) is the most commonly used method for quantitative analysis of local muscle pain and tenderness in pain research. PPS will be evaluated via pressure pain threshold (PPT), or the minimum pressure that induces pain or discomfort. This will be done in the masticatory muscles and neck muscles using a calibrated mechanical algometer (Wagner Instruments, Greenwich, CT 06836-1217) following the protocol described in Silveira et al. PPT measurements have been shown to have good or excellent inter-rater and intra-rater reliability (0.74 to 0.99).

Anxiety will be measured by the general anxiety disorder-7 (GAD-7) instrument.

therapeutic alliance [ Time Frame: at 2 months ]

The therapeutic alliance between the therapist and the patient will be measured at 1 month and at the end of the treatment by using the working alliance sub-scale of the Pain Rehabilitation Expectations Scale (PRES). The PRES is a self-reported clinical intervention-specific assessment tool developed to measure proxy efficacy, motivation/ expectations, and working alliance for rehabilitation interventions in LBP patients

level of expectations [ Time Frame: baseline ]

Patients will be asked to rate their expectations of pain relief at baseline using the Credibility and Expectancy Questionnaire (CEQ). The CEQ tool has been widely used in clinical trials in diverse areas such as psychology (66,67) pharmacology (68) physiotherapy (69), and cognitive-behavioral therapy (70) to determine level of expectations. The CEQ comprises 6- items (2 sets) and two factors (i.e. credibility and expectancy). Items 1 to 3 measure credibility, while items 4 to 6 appraise expectancy. Subjects are asked to rate items on a scale of 1 to 9, with anchors provided for 1 ("not at all), 5 ("somewhat"), and 9 ("very"). Thus, for the expectancy variable a minimum score of 3 points and a maximum of 27 points can be obtained. The CEQ is considered to be a valid and reliable (71) tool to measure the expectancy construct.

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Ages Eligible for Study:

18 Years to 55 Years (Adult)

Sexes Eligible for Study:

Female

Accepts Healthy Volunteers:

No

Criteria

Inclusion Criteria:

Right-handed females 18-55 years of age (TMDs are more prevalent in females);

diagnosed with muscle pain disorders as classified by the new Diagnostic Criteria for Temporomandibular Disorders (DC/TMD);